1. Field of the Invention
The present invention relates to a television broadcast receiver with caption display capability.
2. Description of the Related Art
A television broadcast receiver with caption display capability is known that extracts caption information from a television broadcast signal containing the caption information, and that superimposes, on an image of a television program, the thus extracted caption information as caption (such as closed caption) for monitor output. In the United States of America, the EIA (Electronic Industries Association)-608 and EIA-708 provide standards for closed caption. Broadcast stations can transmit television broadcast signals containing closed caption data specifically designating various parameters for a closed caption output format conforming to these standards, so as to enable a television broadcast receiver to display the closed caption.
The EIA-708 standard provides a specification for a user of a television broadcast receiver to optionally set a part of the parameters. Referring to FIG. 12, which shows a parameter table 130 listing parameters for a closed caption according to a prior art, the parameters include e.g. font type 131, font size 132, foreground color (text color, i.e. character color) 133, background color 134, edge color 135, edge type 136, foreground opacity (text opacity) 137 and background opacity 138. Each of the parameters 131 to 138 includes multiple options 131a to 138a, respectively, such as color options 133a. The user of the television broadcast receiver can adjust these parameters 131 to 138 so as to optionally change or modify the closed caption output format.
In such television broadcast receiver conforming to the EIA-708 standard, the various parameters 131 to 138 are set using e.g. a parameter setting image 150 which is displayed on a monitor as shown in FIG. 13, and which is used by a user to select the parameters 131 to 138. More specifically, for changing the foreground color 133, for example, according to such conventional method of using the parameter setting image 150, the user selects the parameter of foreground color 133 from the parameters, and further selects a desired option (color) from the options (colors) 133a of the foreground color 133. In a similar manner, the user selects a desired option from the options 131a to 138a for each of the parameters 131 to 138. This requires redundant procedures to complete an intended parameter setting.
Furthermore, according to the prior art, the respective parameters 131 to 138 are individually and independently selected. This may cause the following problem, depending on combinations of the options 131a to 138a. More specifically, when one option of a first parameter is selected to change the first parameter, and then one option of a second parameter is selected to change the second parameter, there is a possibility that the option of the first parameter may become invalid due to the selection of the option of the second parameter.
For example, as shown in the parameter table 130 of FIG. 12, according to the options of parameters conforming to the EIA-708 standard, both the foreground (text) opacity 137 and the background opacity 138 include “Transparent” (hereafter referred to as “Foreground (Text) Transparent” and “Background Transparent”, respectively, in case of need). If certain options are first selected from the foreground (text) color 133, edge type 136 and edge color 135, and thereafter the option “Transparent” is selected from the options of the foreground opacity 137, then the first selected certain options of these three parameters become invalid. Similarly, if a certain color is first selected from the background color 134, and thereafter the option “transparent” is selected from the options of the background opacity 138, then the first selected certain option of the background color 134 becomes invalid. Thus, there is a possibility that a user may go through redundant or unnecessary procedures to complete an intended parameter setting.